net.sf.saffron.rel
Class UnionToDistinctRule

java.lang.Object
  |
  +--net.sf.saffron.opt.VolcanoRule
        |
        +--net.sf.saffron.rel.UnionToDistinctRule

public class UnionToDistinctRule

extends VolcanoRule

UnionToDistinctRule translates a distinct UnionRel (all = false) into a DistinctRel on top of a non-distinct UnionRel (all = true).

Field Summary

Fields inherited from class net.sf.saffron.opt.VolcanoRule

description, planner

Constructor Summary

UnionToDistinctRule()

Method Summary

void	onMatch(VolcanoRuleCall call) This method is called every time the rule matches.

Methods inherited from class net.sf.saffron.opt.VolcanoRule

convert, getOutConvention, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

UnionToDistinctRule

public UnionToDistinctRule()

Method Detail

onMatch

public void onMatch(VolcanoRuleCall call)

Description copied from class: VolcanoRule

This method is called every time the rule matches. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back VolcanoRuleCall.transformTo(net.sf.saffron.rel.SaffronRel) to register the expression.

Specified by:

onMatch in class VolcanoRule